Article having ceramic wall with flow turbulators

ABSTRACT

An article includes a ceramic wall that defines at least a side of a passage. The ceramic wall includes a flow turbulator that projects into the passage. The flow turbulator is formed of ceramic matrix composite.

CROSS-REFERENCED TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.15/354,083, which was filed on Nov. 17, 2016.

BACKGROUND

A gas turbine engine typically includes a fan section, a compressorsection, a combustor section and a turbine section. Air entering thecompressor section is compressed and delivered into the combustionsection where it is mixed with fuel and ignited to generate a high-speedexhaust gas flow. The high-speed exhaust gas flow expands through theturbine section to drive the compressor and the fan section. Thecompressor section typically includes low and high pressure compressors,and the turbine section includes low and high pressure turbines.

The high pressure turbine drives the high pressure compressor through anouter shaft to form a high spool, and the low pressure turbine drivesthe low pressure compressor through an inner shaft to form a low spool.The fan section may also be driven by the low inner shaft. A directdrive gas turbine engine includes a fan section driven by the low spoolsuch that the low pressure compressor, low pressure turbine and fansection rotate at a common speed in a common direction.

A speed reduction device, such as an epicyclical gear assembly, may beutilized to drive the fan section such that the fan section may rotateat a speed different than the turbine section. In such enginearchitectures, a shaft driven by one of the turbine sections provides aninput to the epicyclical gear assembly that drives the fan section at areduced speed.

SUMMARY

An article according to an example of the present disclosure includes aceramic wall that defines at least a side of a passage. The ceramic wallincludes a flow turbulator that projects into the passage. The flowturbulator is formed of ceramic matrix composite.

In a further embodiment of any of the foregoing embodiments, the ceramicwall includes a body portion from which the flow turbulators project,and the body portion is formed of ceramic matrix composite having aplurality of fibers disposed in a ceramic matrix.

In a further embodiment of any of the foregoing embodiments, the ceramicmatrix composite of the flow turbulator includes a plurality of fibersdisposed in a ceramic matrix, and the ceramic matrix of the body portionand the ceramic matrix of the flow turbulator have equivalent basecompositions.

In a further embodiment of any of the foregoing embodiments, the basecompositions are silicon-containing.

In a further embodiment of any of the foregoing embodiments, the fibersof the body portion are woven.

In a further embodiment of any of the foregoing embodiments, the ceramicmatrix composite of the flow turbulator includes a plurality of fibersdisposed in a ceramic matrix. The fibers of the body portion have acommon body fiber orientation, and the fibers of the flow turbulatorhave a common turbulator fiber orientation that is transverse to thecommon body fiber orientation.

In a further embodiment of any of the foregoing embodiments, the flowturbulator is an elongated strip.

In a further embodiment of any of the foregoing embodiments, the ceramicmatrix composite of the flow turbulator includes a plurality of fibersdisposed in a ceramic matrix, and the fibers of the flow turbulator areunidirectionally oriented in the elongated direction of the elongatedstrip.

In a further embodiment of any of the foregoing embodiments, the fibersof the flow turbulator have common fiber diameters, and the elongatedstrip has a height of at least two fiber diameters.

In a further embodiment of any of the foregoing embodiments, the fibersof the flow turbulator have common fiber diameters, and the elongatedstrip has a height of at least four fiber diameters.

In a further embodiment of any of the foregoing embodiments, theelongated strip has a height of at least 5 mils (0.127 millimeters).

In a further embodiment of any of the foregoing embodiments, the ceramicwall is in an airfoil section and defines at least a portion of anairfoil profile of the airfoil section.

An airfoil according to an example of the present disclosure includes anairfoil section that defines an airfoil profile. The airfoil sectionincludes a ceramic wall that has an exterior side that defines at leasta portion of the airfoil profile and an interior side that defines atleast a portion of a passage. The interior side of the ceramic wallincludes a flow turbulator that projects into the passage. The flowturbulator is formed of ceramic matrix composite.

In a further embodiment of any of the foregoing embodiments, the ceramicwall includes a body portion from which the flow turbulator projects.The body portion is formed of ceramic matrix composite that has aplurality of fibers disposed in a ceramic matrix. The ceramic matrixcomposite of the flow turbulator includes a plurality of fibers disposedin a ceramic matrix, and the ceramic matrix of the body portion and theceramic matrix of the flow turbulator have equivalent base compositions.

In a further embodiment of any of the foregoing embodiments, the basecompositions are silicon-containing.

In a further embodiment of any of the foregoing embodiments, the fibersof the body portion are woven.

In a further embodiment of any of the foregoing embodiments, the flowturbulator is an elongated strip, and the fibers of the flow turbulatorare unidirectionally oriented in the elongated direction of theelongated strip.

In a further embodiment of any of the foregoing embodiments, the fibersof the flow turbulator have common fiber diameters, and the elongatedstrip has a height of at least two fiber diameters.

A gas turbine engine according to an example of the present disclosureincludes a compressor section, a combustor in fluid communication withthe compressor section, and a turbine section in fluid communicationwith the combustor. One of the turbine section or the compressor sectionincludes an article that has a ceramic wall that defines at least a sideof a passage. The ceramic wall includes a flow turbulator that projectsinto the passage. The flow turbulator is formed of ceramic matrixcomposite.

In a further embodiment of any of the foregoing embodiments, the ceramicwall includes a body portion from which the flow turbulator projects.The body portion is formed of ceramic matrix composite that has aplurality of fibers disposed in a ceramic matrix. The ceramic matrixcomposite of the flow turbulator includes a plurality of fibers disposedin a ceramic matrix, and the ceramic matrix of the body portion and theceramic matrix of the flow turbulator have equivalent base compositions.The flow turbulator is an elongated strip, and the fibers of the flowturbulator are unidirectionally oriented in the elongated direction ofthe elongated strip.

BRIEF DESCRIPTION OF THE DRAWINGS

The various features and advantages of the present disclosure willbecome apparent to those skilled in the art from the following detaileddescription. The drawings that accompany the detailed description can bebriefly described as follows.

FIG. 1 illustrates an example gas turbine engine.

FIG. 2 illustrates an example article having a ceramic wall with flowturbulators.

FIG. 3 illustrates another example ceramic with flow turbulators.

FIG. 4 illustrates a gas turbine engine vane with a ceramic wall havingflow turbulators.

FIG. 5 illustrates an isolated view of the ceramic wall of FIG. 4.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates a gas turbine engine 20. The gasturbine engine 20 is disclosed herein as a two-spool turbofan thatgenerally incorporates a fan section 22, a compressor section 24, acombustor section 26 and a turbine section 28. Alternative enginedesigns can include an augmentor section (not shown) among other systemsor features.

The fan section 22 drives air along a bypass flow path B in a bypassduct defined within a nacelle 15, while the compressor section 24 drivesair along a core flow path C for compression and communication into thecombustor section 26 then expansion through the turbine section 28.Although depicted as a two-spool turbofan gas turbine engine in thedisclosed non-limiting embodiment, the examples herein are not limitedto use with two-spool turbofans and may be applied to other types ofturbomachinery, including direct drive engine architectures, three-spoolengine architectures, and ground-based turbines.

The engine 20 generally includes a low speed spool 30 and a high speedspool 32 mounted for rotation about an engine central longitudinal axisA relative to an engine static structure 36 via several bearing systems38. It should be understood that various bearing systems 38 at variouslocations may alternatively or additionally be provided, and thelocation of bearing systems 38 may be varied as appropriate to theapplication.

The low speed spool 30 generally includes an inner shaft 40 thatinterconnects a fan 42, a first (or low) pressure compressor 44 and afirst (or low) pressure turbine 46. The inner shaft 40 is connected tothe fan 42 through a speed change mechanism, which in exemplary gasturbine engine 20 is illustrated as a geared architecture 48, to drivethe fan 42 at a lower speed than the low speed spool 30.

The high speed spool 32 includes an outer shaft 50 that interconnects asecond (or high) pressure compressor 52 and a second (or high) pressureturbine 54. A combustor 56 is arranged between the high pressurecompressor 52 and the high pressure turbine 54. A mid-turbine frame 57of the engine static structure 36 is arranged generally between the highpressure turbine 54 and the low pressure turbine 46. The mid-turbineframe 57 further supports the bearing systems 38 in the turbine section28. The inner shaft 40 and the outer shaft 50 are concentric and rotatevia bearing systems 38 about the engine central longitudinal axis A,which is collinear with their longitudinal axes.

The core airflow is compressed by the low pressure compressor 44 thenthe high pressure compressor 52, mixed and burned with fuel in thecombustor 56, then expanded over the high pressure turbine 54 and lowpressure turbine 46. The mid-turbine frame 57 includes airfoils 59 whichare in the core airflow path C. The turbines 46, 54 rotationally drivethe respective low speed spool 30 and high speed spool 32 in response tothe expansion. It will be appreciated that each of the positions of thefan section 22, compressor section 24, combustor section 26, turbinesection 28, and fan drive gear system 48 may be varied. For example,gear system 48 may be located aft of combustor section 26 or even aft ofturbine section 28, and fan section 22 may be positioned forward or aftof the location of gear system 48.

The engine 20 in one example is a high-bypass geared aircraft engine. Ina further example, the engine 20 bypass ratio is greater than about six(6), with an example embodiment being greater than about ten (10), thegeared architecture 48 is an epicyclic gear train, such as a planetarygear system or other gear system, with a gear reduction ratio of greaterthan about 2.3 and the low pressure turbine 46 has a pressure ratio thatis greater than about five. In one disclosed embodiment, the engine 20bypass ratio is greater than about ten (10:1), the fan diameter issignificantly larger than that of the low pressure compressor 44, andthe low pressure turbine 46 has a pressure ratio that is greater thanabout five 5:1. Low pressure turbine 46 pressure ratio is pressuremeasured prior to inlet of low pressure turbine 46 as related to thepressure at the outlet of the low pressure turbine 46 prior to anexhaust nozzle. The geared architecture 48 may be an epicycle geartrain, such as a planetary gear system or other gear system, with a gearreduction ratio of greater than about 2.3:1. It should be understood,however, that the above parameters are only exemplary of one embodimentof a geared architecture engine and that the present invention isapplicable to other gas turbine engines, including direct driveturbofans.

A significant amount of thrust is provided by the bypass flow B due tothe high bypass ratio. The fan section 22 of the engine 20 is designedfor a particular flight condition—typically cruise at about 0.8 Mach andabout 35,000 feet. The flight condition of 0.8 Mach and 35,000 ft, withthe engine at its best fuel consumption—also known as “bucket cruiseThrust Specific Fuel Consumption (‘TSFC’)”—is the industry standardparameter of 1 bm of fuel being burned divided by 1 bf of thrust theengine produces at that minimum point. “Low fan pressure ratio” is thepressure ratio across the fan blade alone, without a Fan Exit Guide Vane(“FEGV”) system. The low fan pressure ratio as disclosed hereinaccording to one non-limiting embodiment is less than about 1.45. “Lowcorrected fan tip speed” is the actual fan tip speed in ft/sec dividedby an industry standard temperature correction of [(Tram °R)/(518.7°R)]^(0.5). The “Low corrected fan tip speed” as disclosed hereinaccording to one non-limiting embodiment is less than about 1150ft/second.

In gas turbine engines air is often bled from the compressor for coolingalloy components in the turbine that cannot withstand stoichiometricideal temperatures of fuel burn; however, compressor bleed penalizesengine efficiency. Efficiency is governed by thermodynamics and massflow through the turbine. Efficiency can generally be increased bylowering volume of compressor bleed, increasing velocity of compressorbleed, or increasing temperature of compressor bleed. These goals arechallenging to meet because compressor bleed relies on the pressuredifferential between the compressor and the turbine. That is, the goalsof lower volume, increased velocity, and increased temperature ofcompressor bleed are generally opposite to the goals of high pressureand low temperature compressor bleed desired for achieving good pressuredifferential. In this regard, to facilitate overcoming such challenges,an approach taken in this disclosure is to reduce the need forcompressor bleed and cooling by enhancing the temperature resistancecapability of the turbine or other components exposed to hightemperatures. In particular, thermal resistance can be enhanced at thecompressor exit and turbine inlet.

FIG. 2 illustrates a representative portion of one such component,namely an article 60. For instance, the article 60 can be a turbinevane, as represented at 60 a in FIG. 1, or a compressor vane, asrepresented at 60 b in FIG. 1. As will be appreciated, although theexamples herein may be described in the context of a gas turbine engineor an airfoil, this disclosure is not limited to airfoils, and theexamples may be applicable to other engine components that are exposedto high temperatures, or non-engine articles that are exposed to hightemperatures.

In the illustrated example, the article 60 includes a ceramic wall 62that defines, at least in part, a passage 64. For instance, the passage64 may convey fluid or cooling bleed air, generally represented as flowF. The ceramic wall 62 includes a body portion 62 a and a flowturbulator 66 that projects into the passage 64. In this example, theflow turbulator 66 projects from the body portion 62 a into the passage64. The ceramic wall 62 in the illustrated example includes a pluralityof flow turbulators 66, but may alternatively have fewer flowturbulators 66 than shown or more flow turbulators 66 than shown. Inthis example, the flow turbulators 66 are evenly spaced apart along thepassage 64. The spacings are represented at S1, S2, and S3. For evenspacing, S1=S2=S3. The turbulators 66 disturb the flow F and cause flowmixing. The mixing facilitates heat removal from the ceramic wall 62.Alternatively, the flow turbulators 66 may be non-unfiromly spaced for amore randomized mixing effect. For non-unfirom spacing, S1≠S2≠S3. Inanother alternative, the flow turbulators 66 may have a first sectionthat has first uniform spacings, and a second section that has second,closer uniform spacings. For such spacings, S1=S2 and S1>S3. Thedifferent spacings provide different mixing effects in different regionsof the passage 64.

As the name indicates, the ceramic wall 62 is formed of ceramic. Aceramic is a compound of metallic or metalloid elements bonded withnonmetallic elements or metalloid elements primarily in ionic orcovalent bonds. Example ceramic materials may include, but are notlimited to, oxides, carbides, nitrides, borides, silicides, andcombinations thereof. In further example, the body portion 62 a of theceramic wall 62 may be a monolithic ceramic or a ceramic matrixcomposite (CMC). For example, a monolithic ceramic is composed of asingle, homogenous ceramic material. A composite is composed of two ormore materials that are individually easily distinguishable. A CMC has areinforcement phase, such as ceramic or carbon fibers, dispersed in aceramic matrix formed of oxides, carbides, nitrides, borides, silicides,or combinations thereof.

The flow turbulators 66 of the ceramic wall 62 are formed of ceramicwhich is CMC. For instance, the CMC of the flow turbulators 66 has areinforcement phase, such as ceramic or carbon fibers, dispersed in aceramic matrix formed of oxides, carbides, nitrides, borides, silicides,or combinations thereof. As used herein, the term “fiber” may refer to amonofilament fiber or a fiber tow. A fiber tow includes a bundle offilaments. A single tow may include hundreds or thousands of filaments.

FIG. 3 illustrates a representative portion of another example ceramicwall 162. In this disclosure, like reference numerals designate likeelements where appropriate and reference numerals with the addition ofone-hundred or multiples thereof designate modified elements that areunderstood to incorporate the same features and benefits of thecorresponding elements. In this example, the ceramic wall 162 includes abody portion 162 a and flow turbulators 166 that project from the bodyportion 162 a into the passage 64. The body portion 162 a and the flowturbulators 166 are both formed of CMCs. The CMC of the body portionincludes body fibers 168 a that are disposed in a ceramic body matrix168 b (between and around the fibers 168 a). The CMC of the flowturbulators 166 includes turbulator fibers 170 a that are disposed in aturbulator ceramic matrix 170 b (between and around the fibers 170 a).For example, the fibers 168 a/ 170 a are independently selected fromceramic fibers and carbon fibers. The matrices 168 b/ 170 b areindependently selected from oxides, carbides, nitrides, borides,silicides, or combinations thereof.

In a further example, the ceramic matrices 168 b/ 170 b have equivalentbase compositions. For instance, the predominant ceramic in each ceramicmatrix 168 b/ 170 b is the same composition of ceramic, such as the sameoxide, carbide, nitride, boride, or silicide. In a further example, thepredominant ceramic in each ceramic matrix 168 b/ 170 b is a silicon-containing ceramic, such as but not limited to silicon carbide.

The fibers 168 a of the body portion 162 a may be woven or non-woven,but most typically are non-randomly arranged. In the illustratedexample, the fibers 168 a are woven and include fibers 168 a that areoriented in a common 0 degree direction and other fibers 168 a that areprovided in bundles in a common 90 degree direction. As will beappreciated, the bundles of fibers 168 a could additionally oralternatively have other orientation configurations, such as but notlimited to 0/45 degrees, 0/45/90 degrees, or unidirectional (all 0degrees).

In this example, the flow turbulators 166 are provided as elongatedstrips 172. The strips 172 may be generally rectangular or generallysemi-ovular in cross-section, but other geometries could also be used tocontrol the mixing and turbulence provided by the strips 172. The fibers170 a of the flow turbulators 166 are unidirectionally or commonlyoriented in the direction of elongation E1 of the elongated strips 172.Additionally, the orientation direction of the fibers 170 a of the flowturbulators 166 is transverse to the one or both of the common 0 degreeorientation or the common 90 degree orientation of the fibers 168 a,which may facilitate reinforcing the ceramic wall 162.

The fibers 168 a of the body portion 162 a may provide a texturedsurface in the passage 64, particularly if the fibers 168 a are wovenand cross over and under each other. Although the textured surface mayprovide some flow mixing, the flow turbulators 166 are generally largerthan the height of the texture. For example, the size of the flowturbulators 166 can be represented with reference to the diametric sizeof the fibers 170 a, which may be the same size and composition as thefibers 168 a. The fibers 170 a of the flow turbulators 166 have commonfiber diameters, represented at “d.” For a monofilament fiber thediameter is just the diameter of the filament. For a fiber tow, thediameter is the diametric size of the bundle of filaments. The elongatedstrips 172 have a height, represented at “h,” of at least two fiberdiameters d, where the height is the direction orthogonal to theelongated direction E1 and generally orthogonal to the textured surface.In a further example, the elongated strips 172 have a height of at leastfour fiber diameters d, for a greater turbulating effect. In someexamples, the height is at least 10 fiber diameters and is no more thanapproximately thirty fiber diameters. In one further example, a fibertow is about 5 mils (0.127 millimeters) to about 30 mils (0.762millimeters) in diameter. Therefore, if the height h of the elongatedstrips 172 is two diameters, then the actual height of the strip 172would be about 10 mils (0.254 millimeters) to about 60 mils (1.524millimeters). In another example, if the height h of the elongatedstrips 172 is one diameter, then the actual height of the strip 172would be about 5 mils (0.127 millimeters) to about 30 mils (0.762millimeters).

In an additional example, the size of the flow turbulators 166 isrepresented with reference to the thickness, represented at “t,” of thebody portion 162 a of the ceramic wall 162. For instance, the elongatedstrips 172 have a height of 5% to 50% of the thickness t.

FIG. 4 illustrates another example ceramic wall 262. In this example,the ceramic wall 262 is in the article 60, which is a gas turbine engineturbine vane 74. The turbine vane 74 includes a platform or (inner)endwall 76 and an airfoil section 78 that extends from the endwall 76.Although not shown, the vane 74 may have an outer platform or endwall.The airfoil section 78 may be hollow and can include one or moreinternal passages 64.

The airfoil section 78 defines an airfoil profile, AP, which is theperipheral shape of the airfoil section 78 when viewed in a radialdirection. For example, the airfoil profile has a wing-like shape thatprovides a reaction force via Bernoulli's principle with regard to flowover the airfoil section 78. The airfoil profile generally includes aleading end (LE), a trailing end (TE), a pressure side (PS), and asuction side (SS).

In this example, the airfoil section 78 is formed of a plurality ofdistinct walls or panels 80 that define, at least in part, the airfoilprofile AP. The ceramic wall 262 is or is part of one of the panels 80.

FIG. 5 shows an isolated view of a portion of the ceramic wall 262. Asshown, the body portion 262 a of the ceramic wall 262 includes anexterior side 80 a and an interior side 80 b. The exterior side 80 adefines at least a portion of the airfoil profile AP and the interiorside 80 b defines at least a portion of the passage 64. The flowturbulators 266 project from the body portion 262 a into the passage 64,which may be divided into sub-passages. The ceramic wall 262 mayotherwise be configured as described above for the examples the ceramicwalls 62/162.

The ceramic wall 62/162/262 may be fabricated using generally knownceramic fabrication techniques. For instance, fiber layers may bestacked or laid-up in a desired configuration (e.g. the 0/90, 0/45,0/45/90 configurations described herein) to form a preform. The fiberslayers may be pre-impregnated with a preceramic material, such as apreceramic polymer, that ultimately forms the ceramic matrix of the CMC(in whole or in part). Alternatively or additionally, some or all of theceramic matrix can be deposited subsequent to the stacking of the fiberslayers, such as by chemical vapor deposition.

The fibers of the flow turbulators 66/166/266 will most typically bearranged on the (green) preform in the desired configuration of the flowturbulators 66/166/266. Alternatively, the fibers of the flowturbulators 66/166/266 could be arranged on the preform in a semi-greenstate or fully processed state in which the ceramic matrix of the bodyportion 62 a/ 162 a/ 262 a has been fully or substantially fully formed.For instance, the fibers of the flow turbulators 66/166/266 may bearranged as individual fibers, fiber bundles, fiber tapes, or the like.Similar to the fibers of the body portion 62 a/ 162 a/ 262 a, the fibersof the flow turbulators 66/166/266 may be pre-impregnated with apreceramic material or the ceramic matrix of the flow turbulators66/166/266 may be deposited subsequent to arranging the fibers, bychemical vapor deposition. The preform is then further processed, suchthat the body portion 62 a/ 162 a/ 262 a and flow turbulators 66/166/266are co-processed, to form the final or near final ceramic wall62/162/262. If a preceramic polymer is used, the further processing mayinclude a pyrolysis step to convert the preceramic polymer to ceramic.Alternatively or additionally, chemical vapor deposition may be used todeposit ceramic as the ceramic matrices. The body portion 62 a/ 162 a/262 a and the flow turbulators 66/166/266 do not have to beco-processed; however, the co-processing may facilitate bonding betweenthe body portion 62 a/ 162 a/ 262 a and the flow turbulators 66/166/266by integral formation of the ceramic matrices.

Although a combination of features is shown in the illustrated examples,not all of them need to be combined to realize the benefits of variousembodiments of this disclosure. In other words, a system designedaccording to an embodiment of this disclosure will not necessarilyinclude all of the features shown in any one of the Figures or all ofthe portions schematically shown in the Figures. Moreover, selectedfeatures of one example embodiment may be combined with selectedfeatures of other example embodiments.

The preceding description is exemplary rather than limiting in nature.Variations and modifications to the disclosed examples may becomeapparent to those skilled in the art that do not necessarily depart fromthis disclosure. The scope of legal protection given to this disclosurecan only be determined by studying the following claims.

What is claimed is:
 1. An article comprising: a ceramic matrix compositewall defining at least a side of a passage, the ceramic matrix compositewall including a ceramic matrix composite flow turbulator that projectsinto the passage, wherein the ceramic matrix composite of the wallcomprises woven fibers that are dispersed in a ceramic body matrix. 2.The article as recited in claim 1, wherein the ceramic matrix of thebody portion and the ceramic matrix of the flow turbulator haveequivalent base compositions.
 3. The article as recited in claim 2,wherein the base compositions are silicon-containing.
 4. The article asrecited in claim 1, wherein the woven fibers in the ceramic matrixcomposite wall include a first plurality of fibers that are oriented ina common first direction and second plurality of fibers that areoriented in a common second direction.
 5. The article as recited inclaim 4, wherein the second plurality of fibers includes bundles offibers.
 6. The article as recited in claim 4, wherein the seconddirection is different from the first direction.
 7. The article asrecited in claim 6, wherein the second direction is normal to the firstdirection.
 8. The article as recited in claim 6, wherein the seconddirection is offset from the first direction by 45 degrees.
 9. Thearticle as recited in claim 6, wherein the flow turbulator is anelongated strip.
 10. The article as recited in claim 9, wherein theceramic matrix composite of the flow turbulator includes a plurality offibers disposed in a ceramic matrix, and the fibers of the flowturbulator are unidirectionally oriented in the elongated direction ofthe elongated strip.
 11. The article as recited in claim 10, wherein thefibers of the flow turbulator have common fiber diameters, and theelongated strip has a height of at least two fiber diameters.
 12. Thearticle as recited in claim 10, wherein the fibers of the flowturbulator have common fiber diameters, and the elongated strip has aheight of at least four fiber diameters.
 13. The article as recited inclaim 10, wherein the elongated strip has a height of at least 5 mils(0.127 millimeters).
 14. The article as recited in claim 1, wherein theceramic matrix composite wall is in an airfoil section and defines atleast a portion of an airfoil profile of the airfoil section.
 15. Anairfoil comprising: an airfoil section defining an airfoil profile, theairfoil section including a ceramic wall having an exterior sidedefining at least a portion of the airfoil profile and an interior sidedefining at least a portion of a passage, the wall formed of ceramicmatrix composite comprising woven fibers that are dispersed in a ceramicbody matrix, the interior side of the ceramic wall including a ceramicmatrix composite flow turbulator that projects into the passage.
 16. Theairfoil as recited in claim 15, wherein the woven fibers in the ceramicmatrix composite wall include a first plurality of fibers that areoriented in a common first direction and second plurality of fibers thatare oriented in a common second direction, wherein the second directionis different from the first direction.
 17. The airfoil as recited inclaim 16, wherein the flow turbulator is an elongated strip, and whereinthe ceramic matrix composite of the flow turbulator includes a pluralityof fibers disposed in a ceramic matrix, and the fibers of the flowturbulator are unidirectionally oriented in the elongated direction ofthe elongated strip.
 18. The airfoil as recited in claim 17, wherein thefibers of the flow turbulator have common fiber diameters, and theelongated strip has a height of at least two fiber diameters.
 19. Theairfoil as recited in claim 15, wherein the ceramic matrix of the bodyportion and the ceramic matrix of the flow turbulator have equivalentbase compositions.
 20. A gas turbine engine comprising: a compressorsection; a combustor in fluid communication with the compressor section;and a turbine section in fluid communication with the combustor, atleast one of the turbine section or the compressor section including anarticle having a ceramic matrix composite wall wall defining at least aside of a passage, the ceramic wall including a ceramic matrix compositeflow turbulator that projects into the passage, wherein the ceramicmatrix composit of the wall comprises woven fibers that are dispersed ina ceramic body matrix.